Drill-supporting apparatus

ABSTRACT

Adapted for use drilling steep or horizontal rock faces. A hydraulic cylinder assembly with upper and lower piston rods extending through upper and lower cylinder heads, the piston rods being secured in a piston. A lower end of the lower piston rod is anchored through universal joint to a rock face being drilled, the upper end of the piston rod being secured at an apex of a tripod. The drill is attached to the cylinder with a longitudinal axis of the drill parallel to a longitudinal axis of the cylinder assembly. Provision for admitting water under pressure to an upper cylinder space with a lower cylinder space being connected to a bleeder pipe having a bleeder valve. With the bleeder valve opened a small amount, the drill is fed downwards against the face at a rate which is a function of the amount by which the bleeder valve is opened. The cylinder is moved upwards with respect to the piston rods by similarly introducing water under pressure to an upper cylinder space, so that the hydraulic cylinder also provides means of pulling a drill rod from the hole. Water supply from source used to lubricate and cool the drill.

Waited States Patent {72] Inventors Francis .1. Brennan;

llfiorl llil. Christensen, both 011 Vnnanda Post Office, Vannnda,British Columbia, Canada [21] Appl. No. 21,985

[22] Filed Mar. 23, 1970 [45] Patented Dec. 21,1971

Continuation of application Ser. No. 813,134, Apr. 3, 1969, nowabandoned. This application Mar. 23, 1970, Ser. No. 21,985

[54] DRILL-SUPPORTING APPARATUS 307,792 1 H1884 OConnor 2,708,101 5/1955Lichtblau Primary Examiner-Ernest R. Purser Attorney-Lyle G. TroreyABSTRACT: Adapted for use drilling steep or horizontai rock faces. Ahydraulic cylinder assembly with upper and lower piston rods extendingthrough upper and lower cylinder heads, the piston rods being secured ina piston. A lower end of the lower piston rod is anchored throughuniversal joint to a rock face being drilled, the upper end of thepiston rod being secured at an apex of a tripod. The drill is attachedto the cylinder with a longitudinal axis of the drill parallel to alongitudinal axis of the cylinder assembly. Provision for admittingwater under pressure to an upper cylinder space with a lower cylinderspace being connected to a bleeder pipe having a bleeder valve. With thebleeder valve opened a small amount, the drill is fed downwards againstthe face at a rate which is a function of the amount by which thebleeder valve is opened. The cylinder is moved upwards with respect tothe piston rods by similarly introducing water under pressure to anupper cylinder space, so that the hydraulic cylinder also provides meansof pulling a drill rod from the hole. Water supply from source used tolubricate and cool the drill.

PATENTEDUEBZI an 3,628,614

SHEET 1 OF 4 Francis J. Brennan and Christensen,

PATENTEUIIEBZWII 3528.614

SHEET 2 [1F 4 Francis 1. Brcnilan and K211: hristensen,

r 2 rs Ly 1:; (L. Trorey Agent PATENTEBDEBZHQ?! 31628514 SHEET 3 BF QFranc J.. Brennan and Karl H. Christensen,

Inventors Lyle G. rorey Agent DRILL-SUPPORTING APPARATUS RELATEDAPPLICATION This is a continuation-in-part of our copending applicationSer. No. 8 l 3,l34 filed 3 Apr. 1969 and now abandoned.

FIELD OF THE INVENTION The invention relates to apparatus for supportingfor instance a diamond drill in operating position, and for providingautomatic feed. While the apparatus is particularly suitable for usewith small portable drills, it is adapted for use with large drills.

PRIOR ART During drilling, a force is applied urging a drill bit againsta face, usually rock face, in which a test hole is being drilled. Theshould be axial, and longitudinal motion of the drill penetrating theface should be essentially axial translation.

Means are also required to feed the drill. In a manual drill presscommonly used in a machine shop, the press provides a mechanismrestraining travel of the drill as above, a machinist applies the forceand effects the feed by means of a lever. Ordinarily homogeneousmaterial is being drilled in a machine shop, and mechanism to effectautomatic feed can be relatively simple.

Means to maintain alignment and effect feed of a diamond drill areknown.

Some manual versions of devices used in portable rock drills use a leverto apply force to the drill and to effect feed, being in this respectanalogous to a manual drill press of a machine shop. This involves heavywork, and the drill can be advanced through but a short distance beforerepositioning of the lever is required so that drilling can becontinued. As the hole deepens so that an additional length of the drillrod is required to be added, the drill and lever are disconnected sothat the additional bit drill length can be added. This too is heavywork, and alignment is a problem particularly in initial stages of thedrilling. Automatic devices with power feed as known to the presentinventor are expensive and heavy, and thus are not ordinarily practicalfor use with small portable drills.

SUMMARY OF THE INVENTION The present invention is directed to reducedifficulties and disadvantages of manual and power drill apparatus knownto the present inventors, and to provide simple cheap automaticapparatus powered by fluid pressure of a water supply. Water at suitablepressure is ordinarily available, being used to lubricate and to cleanout a diamond drill test hole.

Apparatus according to the present invention provides a double actinghydraulic cylinder having an upper piston rod extending through an uppercylinder head, and a lower piston rod extending through a lower pistonhead, inner ends of the piston rods being secured in a piston. A lowerend of the lower piston rod terminates in a universal joint, a stubshaft of which is anchored in the rock face. An upper end of the upperpiston rod is secured at an apex ofa supporting means, such as a simpletripod.

A guide rod is secured externally to the cylinder parallel to a commonaxis of the cylinder the piston and the rods. The drill is mounted onthe guide rod with the drill rod parallel to the common axis, meansbeing provided for the drill to be movable upwards and downwards of theguide rod, or intermediate ly. It is seen that the universal and thetripod thus provide means to orient the drill rod in a directionaccording to that in which the hole is to be drilled.

Water is used, as has been explained for lubricating the drill andflushing the drill hole, hence a supply of water under pressure isavailable.

A selector valve can selectively be set in position as follows: up, todirect water under pressure to an upper cylinder space between thepiston and the upper cylinder head, with a lower cylinder space definedbetween the piston and the lower cylinder head being connected to a.bleeder pipe discharging to atmosphere through a manually controlledvalve; in a down position water under pressure is directed to the lowercylinder space with the upper cylinder space then being connected to thebleeder pipe; and in an off position at which all valve ports areclosed.

Both cylinder spaces being charged with water, it is seen that settingthe valve to admit water to pressurize to the lower cylinder space willnot cause the cylinder to move if the bleeder valve is closed.Consequently, with the valve so positioned, opening of the bleeder valveby a slight amount causes the cylinder, and with it the drill and thedrill rod, to move downward at a rate according to the amount by whichthe bleeder valve is open. It is seen that: nice control of feed at arate according to the opening of the bleeder valve is thus effected, theforce applied to the drill rod urging it downwards depends uponresistance encountered by the drillthis depends upon rate of feed andupon the materialand can attain a maximum equal to supply pressureavailable at the valve times piston area, the maximum being approachedas the drill rod approaches stallwhen the available force isinsufficient to continue to advance the drill. Maximum rate of feedvaries directly as available flow rate, and inversely as the pistonarea.

Hereinafter unless otherwise stated, supply pressure" means pressureavailable at the selector valve, viz pressure at the pump, less line andleakage loss, and less any pressure drop resulting from use of the waterin the drill. When the drill is secured to the guide rod in a fixedportion, it is locked against the guide rod, and rotation of thecylinder about the piston is restained by large cup seals mounted onopposite faces of the piston. The cup seals are of resilient material soas to be expanded outwards by the pressure within the cylinder spaces,thus restraining the cylinder from rotation about the common axis.

Structure as above provides means to apply force urging the drill roddownwards against the face, an equal and opposite force arising at theanchor. These forces are parallel producing a first moment, thestructure providing means to apply an equal and opposite restrainingmoment. Means are also provided to effect control of feed of the drillrod, the apparatus being constructed and arranged to effect that feed ofthe drill rod is essentially axial motion of translation at adeterminate rate, maintaining alignment as the drilling progresses. Thestructure also provides means to pull the drill rod from the hole.

A detail description following related to drawings gives exemplificationof structure according to the present invention which, however, can beexpressed by means other than those particularly described andillustrated.

DESCRIPTION OF THE DRAWINGS FIG. 11 is an elevation of apparatusaccording to the invention, shown with a conventional portable diamonddrill,

FIG. 2 is a large scale plan of a part of the apparatus as seen from 2-2FIG. 1,

FIG. 3 is a fragmented detail elevation showing a fluid cylinderassembly, the drill, and a part of a tripod,

FIG. 3A is a plan showing structure at an apex of the tripod as seenfrom 3A-3A, FIG. 3,

FIG. d is a fragmented section through the fluid cylinder showing ananchor means, some parts not being shown in section,

FIG. 5 is a fragmented partly sectioned detail elevation of a portion ofthe cylinder showing mounting means for the drill,

FIG. 6 is a fragmented side elevation of a rod-pulling means,

FIG. 7 is a section on 7-7 FIG. 6,

FIG. 8 is a force diagram showing forces on the fluid cylinder assemblyand drill,

FIG. 9 is a top plan detail of an alternative collar construction,

FIG. 10 is an elevation of the collar shown in FIG. 9.

DETAILED DESCRIPTION The portable drill, FIGS. 1 and 3 The portablediamond drill designated generally 10 in FIG. 1 is driven by an internalcombustion engine 1 1. The drill has a tubular drive shaft 12 which isthreaded to accept a drill rod 14, having a longitudinal axis designated14.1 in FIG. 3 only. The drill rod made up of lengths of hollow drillrod 15, screwed together at joints 16. A diamond drill bit 17, FIG. 3only, is secured to a lower end of the drill rod.

Water for flushing and cooling enters the drill through a pressure hose18 from a pump 19 drawing water from a source, not shown. The water,which is typically at 50 to I pounds pressure, passes through the shaft12 and the hollow drill rod 14, cooling the bit and flushing materialaway from a bottom face of a hole been drilled. The pump 19 is of a typeother than positive displacement, e.g., centrifugal.

Portable diamond drills of this kind are well known, further details ofconstruction, and of operation except as directly related to the instantapparatus, are not deemed to be necessary.

Drill supporting apparatus, FIGS. 1 and 4, fluid cylinder assembly andtripod In FIG. 1 the drill-supporting apparatus generally 20, is shownholding the drill 10 in position for drilling a test hole 23 in agenerally horizontal rock face 22. The supporting apparatus includessupport means, viz a tripod 24 having a apex 24.1, and a double-actingfluid cylinder assembly 25 a piston rod of which is secured at the apex,the apparatus feeding the drill rod and maintaining alignment asdrilling progresses, and also withdrawing the drill rod from the testhole.

Referring particularly to FIG. 4, the cylinder assembly 25 has adouble-acting cylinder 25.1 having a piston 26, aligned upper and lowerpiston rods 27A, and 278 secured in opposite faces of the piston 26 andbeing extensible and retractible through upper and lower cylinder heads28 and 29 providing a range of motion of the cylinder relative to thepiston between upper and lower limits. The cylinder and piston rods havea common axis 30, the rods passing through pressure bushes 31 and 31.1.

An upper cup seal 32 has a base 32.1 and a sidewall 32.2, the base beingsecured to an upper face of the piston 26 so as to be concave upwards asshown. A lower cup seal 33 has a base 33.1 and a sidewall 33.2, the basebeing secured against a lower face of the piston 26 so as to be concavedownwards as shown, both cup seals being of known flexible material.Means generally 36 anchor a lower end of the lower piston rod in theface.

Anchor means, FIG. 4.

A universal joint 38 has a lower stub shaft 39, a lower end of the lowerpiston rod 278 being secured in the universal joint as seen at 40. Ahole 42 is drilled in the face 22, the hole having a depth and diameterto accept the stub shaft 39. A wedge 43 driven as shown forces the stubshaft 39 against a sidewall of the hole 42, securing the shaft in thehole. To provide increased bearing area of the wedge against the shaft,the wedge can have an inner face 43.1 conforming to the shaft.

Structure at the apex of the tripod, FIGS. 3 and 3A The tripod 24 haslegs 44, 45, 46, all three legs appearing in FIGS. 3A only. Upper endsof the tripod legs are secured by ball and socket means 47,48, 49, in acollar 53 at the apex 24.1, the collar having an inside diameter toaccept the upper piston rod 27A sliding therethrough. Upper and loweradjustable stops 55 and 56 are moveable upwards and downwards of thepiston rod 27A being securable in an adjusted position by tighteningscrews 57 and 58 respectively. The upper stop 55 can be placed to bearagainst an upper end wall 59 of the collar 53, so that downward movementof the piston rod 27A is stopped, resisted by compressive reactions inthe legs. The stop 55 is shown so positioned in FIG. 1 only. Structureas above, designated generally 60, and alternative later described, ismeans to secure the upper piston rod at the apex of the tripod.

Fluid circuit, FIGS. 1 and 3 Referring to FIGS. 1 and 3, control meansgenerally 62 includes a four-way selector valve 63 secured by a bracket65 to the cylinder 25.1, the valve being operated by a lever 66.

A pressure hose 68 is connected to a junction 67 of the pressure hose 18so that fluid, namely water under pressure from the pump 19, enters thepressure hose 68 being an intake hose of the four-way valve 63.Discharge hoses 69 and 70 lead respectively to the upper and lowercylinder spaces 34, 35 (FIG. 4) a bleeder pipe 72 having a bleeder valve73 operated by hand wheel 74 being provided. The four-way valve 63 is ofa common type obtainable from ordinary trade sources and the lever 66can be selectively set in positions as follows: up, to direct the fluidunder pressure through the hose 69 to the upper cylinder space 34, thehose 70 from the lower cylinder space 35 being connected to the bleederpipe 72; down, to direct the fluid under pressure to the lower cylinderspace 35 with the upper cylinder space then being connected to thebleeder pipe, off at which all valve ports are closed.

A manual relief valve 75 FIG. 1, close to the pump is to relieve a headwhich might exist in the hose 18 when the pump is at an elevation muchbelow the drill. The valve 75 discharges to atmosphere through an outlet76, and can be opened to facilitate starting the pump.

Connection of the drill to the cylinder assembly, FIGS. 2, 3, and 5.

The drill is secured to the cylinder assembly by means generally withthe drill rod axis 14.1 maintained parallel to the piston rod axisthrough out a range of vertical travel of the drill relative to thecylinder, the drill rod moving axially through the range of travel. Theforegoing is effected by means including a guide rod 81 having spacedholes centerlines of which are aligned in a radial plane through thelongitudinal axis of the rod, two such holes designated 82 and 82.1being shown in FIG. 5. A longitudinal groove 83 extends between theholes, the groove having a depth materially less than that of the holes.A bracket 84, secured to the cylinder 25.1 carries a sleeve 85 having aninside diameter such as to accept the rod 81 sliding therewithin. Aholder 86 contains a detent 87 urged outwards by a compression spring 88so that the detent engages the hole 82 when detent and hole are inregister and extending outwards so as to be engaged by a sidewall of thegroove 83 when the drill is moved axially. A latch pin 89 secured to thedetent is movable within a latch slot 90 so that the detent can belatched out of engagement with the hole. Referring to FIG. 1, it is seenthat the drill can be moved upwards and downwards of the rod 81 andlocked in a selected position with respect to the cylinder by engagementof the detent 87 in one of the spaced holes such as 82 FIG. 5, the drillrod axis being maintained parallel to the piston rod axis.

Cup seal action, FIGS. 3 and 4 The system being full with the selectorvalve 63 in the off position the cylinder cannot be moved up or down byan external force, and rotation will be resisted since both the cupseals 32 and 33 FIG. 4 are expanded until or unless pressure leaks offthrough the bushes 31 and 31.1.

When the lever is up and the bleeder valve 73 open, with essentially noresistance to motion of the cylinder, pressure in the cylinder spaces ismuch below supply pressure in the cylinder spaces is much below supplypressure hence the cup seals are only slightly expanded, thus thecylinder can be rotated so as, for instance, to swing the drill tofacilitate adding a rod length, and for subsequent alignment. Duringdrilling pressure builds up because of resistance encountered by thedrill in penetrating the face, and can approach supply pressure. Henceduring drilling the cup seals expanded, restraining rotation. As thedrill rod axis 14.1 is maintained parallel to the piston rod axis, vizthe common axis 30, and rotation of the drill rod about the piston rodaxis is restrained, the apparatus provides means to effect that downwardmotion of the drill rod penetrating the face is axial translation.Rod-pulling means, FIGS. 3, 6, and 7 The apparatus 20 is provided withmeans generally 100 to pull the drill rod M from a test hole. Therod-pulling means 166 includes a pulley 101 which is mounted on aspindle 102 secured to the upper cylinder head 28. The universal joint3% has an outwardly projecting bracket 104 having an open eye 105adapted to receive a ferrule. A cable 108 has one end terminated in aneye 106, an opposite end having a ferrule 109 for attachment of thecable in the eye 105.

The rod-pulling means 101) includes wedge clamp means generally 1141(FIG. 7) having a U-shaped fitting 115, a pivot pin bolt passing throughspaced opposite arms 117 of the U. A lever 113 is journaled on the bolt116 the lever having an eccentric cam 119 at an inner end, the outer endofthe lever ll 18 having a ring 120 in which the cable hook 110 issecurable.

To prepare for rod pulling after drilling has stopped, the four-wayvalve 63 is moved to the up position and the bleeder valve 73 isslightly opened to relieve the downward force, and the drive shaft 12 isdisconnected from the drill rod 14. When pressure in the cylinder spacesis relieved, as explained, the cylinder can be rotated about the piston26. The cylinder is then rotated, the drive shaft 12 is moved clear ofthe drill rod M, and the pulley is positioned above and alongside thedrill rod as best seen in FIG. 7. The ferrule 109 of the cable 103 isattached to the universal joint 38 by engaging the ferrule 109 in theopen eye 105 that is to say is secured in a fixed position, and thecable is trained over the pulley 101. with the hook 110 freelysuspended. The wedge clamp 114 is slipped over the top of the drill rod14, and the cable hook 110 is attached to the lever 118 by engaging thehook 110 in the ring 120. At this. time the lever 118 is downwardlyinclined as shown in FIG. 6 with the eccentric 119 disengaged from thedrill rod 14.

The lever 66 of the four-way valve 63 is then positioned to open thevalve and allow water under pressure to enter the upper cylinder space34 thus raising the cylinder. With initial movement of the cylinderupwards, clamping occurs from rotation of the lever 118, and furtherupward movement of the cylinder causes the cable 118 to pull the drillrod upwards through a distance twice that through which the cylindermoves. When the cylinder is lowered, the eccentric can releases and theclamp drops downward to a new position. The cylinder 25 is movedalternatively upward and downward each time the cylinder is at itslowest position the eccentric 119 takes a new grip on the drill rod 14so that the rod is progressively pulled from the test hole.

In this way drill rod pulling is accomplished by one operator withoutneed of auxiliary equipment commonly used to extract a buried drill rod.

The apparatus above described serves to support and feed a portablediamond drill and, in addition, provides power needed to remove a drillrod from a test hole. The several parts of the apparatus can bedismantled to form a bundle of a size suitable for shipping into adrilling site by helicopter, by packhorse, or by back-packing. Theapparatus utilizes power available for the normal operation of aportable diamond drill viz, pressure supplied by the pump which deliverscooling and cleanout water to the drill bit.

OPERATION Drilling in carrying out a drilling operation, the hole 42FIGS. 1 and 4 is drilled, and the universal stub shaft 39 is wedgedsecurely in the hole. It is seen that alignment of the drill axis 14.!is parallel to that of the piston axis 30 and, because of the universal36, is independent of direction in which the hole 42 for the anchor isdrilled.

Before assembling the tripod to the piston rod, the lever 66 of thefour-way control valve 63 is operated so as to move the cylinder 25.1FIG. 3 downwards, the upper stop 55 is removed, and the lower stop 56 isloosened. The collar 53 of the tripod is now assembled to the upperpiston rod 27A, and the tripod legs positioned so that the lower pistonrod 278 is orientated in a direction according to that in which the testhole 23 is to be drilled. The lower stop 66 can be fixed in a convenientposition so as to limit downward movement of the collar. The tripod legshave pointed ends 121. FlG. 1 so as to minimize tendency to slip. Whenthe legs are properly positioned, the upper stop 55 is replaced, andslid towards on the piston rod 27A against the upper end wall 59, FIG.3, of the collar 53 and the screw 57 is tightened securing the stop inposition.

The drill is now assembled to the guide rod fill and a single length ofdrill rod inserted in the hollow drive shaft 12, with the bit 17installed at the lower end of the rod. A short rod length is isordinarily used as a first length. The drill is positioned near thelower end of the cylinder 25.1 so that the short length of drill rod canbe used to start the test hole 23, with initial drilling to a depth of afew inches to serve as a pilot hole. The lever 66 of the four-wayselector valve 63 is moved from the closed position to the down positionto admit fluid to the lower cylinder space 24. This causes the cylinderand drill to move downward toward the face 2.2 and, with the enginerunning, initial drilling commences. Feed is regulated as laterdescribed.

When the pilot hole is sufficiently deep the drill is withdrawn aspreviously described to provide space for insertion of a drill rod 15 ofnormal length. It has been explained that the cylinder 25.1 can be swungabout the piston rod so that the drill rod 15 can be swung in registerwith the initial part of the hole already drilled. With the bleedervalve 73 closed, the lever 66 is moved to admit. water under pressure tothe lower cylinder spaces, pressurization as above causes the sidewallsof both cup seals to be expanded against the inner surface of thecylinder so as to effect locking against rotation of the cylinder withrespect to the piston and piston rods. With the lever 66 remaining inthe position above, that is to say delivering pressure to the lowercylinder space 35, the bleeder valve 73 is opened by a small amount toallow some of the water present in the upper cylinder space to bleed offand discharge through the pipe 72. Since water under pressure is stillbeing directed to the lower cylinder space 35, the bleeding off of waterfrom the upper cylinder space causes the cylinder 25.1, and with it thedrill, to move downwards so feeding the drill at a speed dependent uponthe amount by which the bleeder valve is open. It is seen that directingfluid, i.e., water under pressure, to the lower cylinder space andbleeding off as above described provides means to effect nice control offeed, feed of the drill rod being a function of the amount by which thebleeder valve is opened increasing within increase of bleeding, andbeing decreased with decrease of bleeding.

Rate of feed is adjusted according to the experience of the operator towhat he judges to be optimum for the type of rock being drilled. It isto be noted that rate of feed is determined by rate of bleeding, that isto say by the amount by which the valve 73 is opened. 1f the drillstrikes a fissure or soft spot it does not drop suddenly, but continues.to advance at the determinate rate above. This is of advantage inreducing damage which can and does result in these circumstances. Someair lock can occur, for instance in the cup seal 33, hence in entering afissure the drill can advance a short distance at a speed greater thanthe feed above.

As the drilling progresses, the piston 26 approaches the end of itsstroke whereupon the motor 11 is stopped, the detent 67 is disengagedand the control valve is operated to raise the cylinder 25 towards theupper end of its stroke until the detent 87 is reengaged in a nearesthigher hole 62 the groove 63 facilitating reengagement. Drilling is nowcontinued until an upper end of the first length of pipe 15 is justabove the face 22. The drill rod is now disconnected from the driveshaft and the drill raised, as before described, to a position forattachment of a second length of drill rod to the drive shaft and to thefirst length of drill pipe. Drilling can now be resumed. It is to benoted that lifting of the drill after disconnection of the rod iseffected by water pressure, and that an entire drilling operation canthus be carried out by one operator since manhandling is limited toattaching the drill rod length and maneuvering the drill into position.Forces on the drill and supporting structure, FIG. 1

With the drill being fed into the hole, as described, there is an upwardreaction upon the drill rod. This is resisted by a downward pull on thepiston rod 278, see FIG. 1, which downward pull is exerted by the anchormeans 36 through the universal 38.

These two forces being equal and opposite produce a couple. Restraint iseffected by (at least) one tripod leg in compression resulting in anupward force against the collar 53, exerted by a leg in compression, theupward force on the collar having a vertical component upwards, and ahorizontal component. The horizontal component together with an equaland opposite horizontal reaction at the anchor means provides a contrarymovement and the upward force component at the collar is added todownward force required to be exerted by the anchor, since the downwardforce on the collar tends to drive the tripod leg downwards.

If the upper stop 52 is not initially placed against the upper end wall59 of the collar, it is seen that undesirable bending moment can beintroduced causing the drill to tend to travel downwards other than in astraight line and, in an extreme case, causing breakage or other damage.

When the first few inches of initial drilling has been completed, beforeattaching the full length of drill rod check is to be made that theclamp 55 is still in contact with the end wall 59. It is seen that,stress having been removed, initial settling of the tripod leg will showas space between the end wall of the collar and the upper stop 55. Atthis time, and before recommencing drilling, any required adjustment ofthe position of the stop 55 is to be effected. It is prudent to effect asimilar check after at least the first upwards repositioning of thecylinder.

Force diagram, FIG. 8

For conditions illustrated in FIG. 1 and neglecting torsion on thedrill, there is an upward reaction R on the drill bit 17 in an axialdirection and an equal and opposite force V exerted by resistance of theanchor means 36 from being pulled out of the hole in which it is wedged.These equal and opposite forces, which are parallel, produce a couplehaving a first moment M-l, clockwise as seen in FIG. 8.

The moment M-l is resisted by an equal and opposite restraining momentM-2 as shown, arising from a force F considered as being applied by theleg 45 FIG. 1the force being axial of the leg against the stop 55. Theforce F is shown in broken outline and having a component h normal tothe piston rod axis, and an axial component v. Effectively, the stop canbe considered as being in a broken outline position 45.1 where the leg55 produced would intersect the upper piston rod 27A. With 55.1 being ata height H above the face 22, and with the drill rod 14 being spacedfrom the piston rod 27A by a distance D, taking moments about theuniversal 38 we have the first moment M-l of magnitude RD plus theopposite restraining moment h, H equal to zero, whence Typically D/Hmight be say ten, consequently h typically would be equal to R/lO. Theleg 45, and consequently the force F, is ordinarily at an acute angle tothe piston rod, so that the component v acting on the effective stop55.1 is ordinarily rather larger than h. Total downward force at theanchor means 36 is thus V+v, where v is a reaction equal and opposite tov.

The component h at the stop is balanced by an equal and opposite force hat the universal 38, applied by the wedge means 36. It is to be notedthat the tripod leg 45 is effectively pin jointed at its lower end 121(FIG. 1) and compressive load cannot be applied to the leg until orunless, see FIG. 3, the upper end wall of the collar 53 comes intocontact with the upper stop 55. Consequently, the anchor having auniversal joint, undesirable bending stress can arise in the drill rodwhen it has penetrated to any considerable depth. Bending stress can soarise particularly from play between the collar and the upper stop, orfrom reflection of the leg 45 considered as a long column, or fromslippage at the lower end 121 of a leg. A possible position of the drillrod 14 under these conditions is shown (in an exaggerated amount) inbroken outline at 14.1. In the broken outline position the drill rod14.1 is straight when there has been little penetration of the bit, andis curved as a strained cantilever when the bit has penetrated amaterial distance. It is seen then that having the stop 55 adjustablefor position as described gives opportunity for the lower end of thetripod leg 55 to find firm footing, and to effect adjustment for anycreep which might occur as the drilling progresses-so providing means tomaintain the drill rod 14 essentially parallel to the piston rod duringdrilling, that is to say providing means to effect that feed of thedrill rod is essentially axial motion of translation at a rateaccordingto, as explained above, rate of bleeding.

The reaction R is equal to the force exerted by the drill rod urging thebit against the bottom face of the test hole. It approaches a maximumequal to water pressure times piston area when, or if, this force isinsufficient to cause the bit to continue to penetrate the bottom face,so that it stalls. Under these conditions with the bleeder valve 73 wideopen, rate of bleeding approaches zero as stalling is approached. Whilebleeding rate is a linear junction of feed rate, the bleeder valvecontrols feed in a manner analogous to control of speed of a car bythrottle, speed of the car and feed of the drill depend upon power andload as well as upon throttle, or bleeder valve, opening.

In pulling the drill rod, directions of forces and reactions shown inFIG. 8 are reversed. A moment still arises as M-l but of oppositedirection, and a corresponding restraining moment as M-Z has an oppositedirection.

ALTERNATIVE COLLAR CONSTRUCTION FIGS. 9 and 10 Referring to FIGS. 9 and10, an alternative collar assembly generally 30 has lugs 131 and 132extending radially outwards and spaced at as shown. The collar assemblyhas a hollow cylindrical body 134 with which the lugs 135 areeffectively integral, the body having a lower portion 135 of reduceddiameter defining a collar 136. A short hollow cylindrical sleeve 137has an inside diameter to accept the reduced diameter portion 135 so asto be rotatable thereon. The sleeve 137 has an upturned lug 138 having abore 139 as shown, the lugs 131 and 132 having corresponding bores 141and 142 circumferentially aligned with the bore 139, as shown. The lug138 is adapted to receive a fixture 143 (shown in FIG. 9 only) threadedat an outer end as shown at 144, to receive a leg which can be drill rodlengths. The body 134 has an upper end wall 145 adapted to bear againstthe upper stop 55 as previously described.

Means such as the fixture 143 are capable of rotation with respect tothe collar in a vertical planethe piston rod being considered to bevertical. Since the collar assembly 130 is rotatable about the pistonrod, and can also slide up and down the piston rod, there is a range ofadjustment to obtain a suitable position for the lower end of one tripodleg. Once the lower end of a leg attached, for instance, to the lug 131has been positioned, this restricts available range of position for thelower end of a tripod leg attached to the lug 132. A balland-socketarrangement, as previously described, can be used for attachment of aleg to the lug 132, the ball and socket giving a greater choice ofpositions for the lower end of the leg, under a condition as above. Itis seen that the sleeve 137 permits the leg attached to its lug 138 tobe rotated to a suitable position, notwithstanding another leg or legshave already been positioned. A ball-and-socket joint can alternativelybe used here to give a greater range.

The tripod construction shown in FIG. 1 can be used drilling faces whichare not horizontal. It is seen that with a steep face approaching thevertical when the anchor means has been secured, adequate restraint cansometimes be effected using only two tripod legs. Working on anirregular face, particularly a steep face, the collar alternative 130can be of particular advantage.

The collar 53 FIG. 3 with universally jointed legs, the collar 130 FIG.9 and 10 with one leg independently rotatable and attachment means suchthat each leg rotated in a plane containing the axis of the piston rod,a collar embodiment having legs attached by means such as the means 1 13FIG. 9 but otherwise similar to the collar 53, and a collar embodimentas FIGS. 9 and lit) with at least one leg being secured by ball andsocket means, are all, see FIG. 8, means to apply a restraining momentM-2 to counteract the moment M-l arising from drill bit anchor meansreaction as explained, and provide structure alternative to thatdescribed with reference to the means 60 FIG. 3.

FURTHER CONSIDERATIONS The detail description has been related to adrill driven by an internal combustion engine. In underground workings,a fluid motor would be used to drive the drill. Conditions determiningrate of feed of the drill, and maximum force urging the drill againstthe face, have been stated prior to the detail description. Withstructure as exemplified in the detail description, these limits areapparent it being understood that, by supply pressure, is meant pressureavailable at the valve 63. While a positive displacement pump could beused, to do so involves difficulty. Centrifugal pump supply, or gravitysupply, avoids such difficulty.

Referring to the guide rod 81 FIG. 3, it is seen that the rod extendsbeyond each end of the cylinder 25.1 and thus can have a length of, say,twice the range of motion, or stroke, of the cylinder with respect tothe piston. Drilling being commenced with the drill at a position nearthe upper end of the guide rod, when the drilling has continued for thelength of the stroke the drill can be repositioned at intermediately ofthe guide rod so as to sink the drill further. Repositioning near thelower end of the guide rod enables a drill rod of standard length to beburied, notwithstanding the cylinder has a stroke much less than thelength of the drill rod-as exemplified above the stroke is aboutone-third ofthe length of a standard rod. Thus the cylinder can berelatively small. In FIG. 1 the drill is shown repositioning near thelower end of the guide rod, with the cylinder having commenced itsdownward stroke.

We claim:

1. An apparatus for supporting a drill the apparatus including a drillrod 14 having a longitudinal axis 14.1, the apparatus feeding the drilland maintaining alignment as drilling ofa face progresses; the apparatusincluding,

a. means 25 to apply a force urging the drill rod 14- against the facebeing drilled, the force having a reaction R FIG.

b. means 36 to apply an opposite force V equal in magnitude and oppositein direction to the reaction producing a couple having a first momentM-1,

c. means 34$, 59, 55, 36 to apply an opposite restraining moment M-2equal in magnitude to the first moment,

d. means 25, '72, 73 to effect control offeed ofthe drill rod,constructed and arranged to effect that feed of the drill rod isessentially motion of translation at a determinate rate along thelongitudinal axis produced, maintaining alignment as the drillingprogresses.

2. An apparatus as defined in claim 1, and

e. means 100 to move the drill in a direction opposite to the feed.

3. An apparatus as defined in claim 2 wherein the means a. applying theforce includes i. a double acting fluid cylinder assembly 25 having, apiston 26 with upper and lower faces, and aligned upper and lower pistonrods 27A, 278 secured in the piston and being extensible and retractiblethrough upper and lower cylinder heads 28, 29 providing a lllll) rangeof motion of the cylinder relative to the piston, the piston rods pistonand cylinder having a common axis 311, upper and lower cylinder spaces34, 35 being defined respectively between the upper and lower cylinderheads and the upper and lower faces of the piston,

ii. means 30 to secure the drill to the cylinder, with the drill rodparallel to the common axis,

iii. a support means 24 having an apex 241.1 and means tit) to securethe upper piston rod at the apex,

iv. means 62 to direct fluid under pressure to the lower cylinder space35 with the upper cylinder space 341 then being connected to a bleederpipe 72, the fluid under pressure acting upon the piston tending to movethe cylinder downward so applying the force to the drill rod, fluid inthe upper cylinder space being free to discharge bleeding off throughthe bleeder pipe.

4. A combination as defined in claim 3 wherein,

i. the means I: to apply the opposite force includes means 36 anchoringa lower end of the lower piston rod in the face.

5. A combination as defined in claim 4, the means anchoring the lowerend of the piston rod including,

ii. a universal joint 33 the lower end of the lower piston rod beingsecured ll) in the universal joint, a stub shaft 39 of the universaljoint being secured in. a hole d2 of the face.

6. A combination as defined in claim 3, the means d to effect control offeed including;

i. a bleeder valve 73 of the bleeder pipe, rate of bleeding beingcontrolled according to an amount by which the bleeder valve is opened,rate of relative motion of the cylinder to the piston and feed of thedrill being a function of the amount by which the bleeder valve isopened.

'7. A combination as defined in claim 6, wherein the means e to move thedrill in a direction opposite to the feed includes i. means 62 to directfluid under pressure to the upper cylinder space 34 the lower cylinderspace 35 then being connected to the bleeder pipe, the lower cylinderspace being free to discharge bleeding off through the bleeder pipe thefluid under pressure acting upon the piston applying a force urging thecylinder and the drill to move upwards to pull the drill rod from a testhole drilled in the face.

8. A combination as defined in claim 7, the means to secure the drill tothe cylinder as aforesaid including,

i. a guide rod 31 having longitudinally spaced holes,

ii. a bracket secured to the cylinder, the bracket having a sleevehaving an inside diameter such as to accept the guide rod slidingtherewithin,

iii. a detent 87 of the bracket spring urged to enter a hole so as tolock the drill in a selected position with respect to the cylinder,constructed and arranged for the drill rod to be axially movablerelative the cylinder throughout a range of travel between the selectedpositions.

9. A combination as defined in claim :8, and

iv. a longitudinal groove extending between the holes, the detentengaging a sidewall of the groove when the drill is moved axially asaforesaid,

v. a latch pin 89 movable in a latch slot 90 for latching the detentclear of the holes while still engaging the groove sidewall.

10. A combination as defined in claim 7, wherein the means e. to movethe drill rod in a direction opposite to the feed further includes,

ii. a pulley 101 secured to the cylinder iii. a wedge clamp means 114having an eccentric cam 119 adapted to engage the drill rod, the wedgeclamp being movable between upper and lower positions of a range ofmotion relative to the drill rod,

iv. a cable 108 passing around the pulley and having one end secured tothe clamping means with an opposite end secured in a fixed position sothat force urging the drill to move as aforesaid is applied by the cableto the wedge clamp means.

1 1. A combination as defined in claim 10 and wherein,

iv. the wedge clamp has a lever, pivoted between inner and outer endsthereof, the cable being secured to the outer end of the lever,

v. the eccentric cam being at the inner end of the lever and disengagedfrom the drill rod until force, applied as aforesaid by the cable to theouter end of the lever, rotates the lever engaging the eccentric camwith the drill rod so that, when the cylinder is moved alternativelyupward and downward, each time the cylinder is at a lowest position ofits range of motion the eccentric takes a new grip on the drill rod sothat it is progressively pulled from the test hole.

12. A combination as defined inlclaim 3, wherein the means 60 to securethe upper piston rod at the apex of the support means includes,

a collar 53 having an inside diameter to accept the upper piston rodsliding therethrough,

legs of the support means being mounted in the collar to swing withrespect thereto,

--an upper adjustable stop 55 movable upwards and downwards on thepiston rod and being securable to the piston rod bearing against anupper end wall of the collar.

13. A combination as defined in claim 12 with ball and socket means 47mounting a leg in the collar.

14. A combination as defined in claim 12, the collar having a shorthollow cylindrical sleeve 137 FIG. 10 rotatable of the collar, a legbeing mounted in the sleeve to swing with respect thereto.

15. A combination as defined in claim 3, the double-acting fluid pistonassembly further including vii. an upper cup seal 32 of flexiblematerial, the seal having a base 32.1 and a sidewall 32.2, the basebeing secured against an upper face of the piston 26 so as to be concaveupwards viii. a similar lower cup seal 32 secured concave downwards to alower face of the piston, adapted for the sidewalls of the seals to beexpanded against the cylinder so as to effect restraint against rotationof the cylinder with respect to the piston.

16. A combination as defined in claim 15, and means 62 to direct fluidunder pressure to one cylinder space 34 or 35 with fluid under pressurebeing in a remaining cylinder space 35 or 34, so as to expand the cupseals as aforesaid.

17. An apparatus as defined in claim 1, and means to pull the drill rodfrom a test hole drilled in the face.

1. An apparatus for supporting a drill the apparatus including a drillrod 14 having a longitudinal axis 14.1, the apparatus feeding the drilland maintaining alignment as drilling of a face progresses; theapparatus including, a. means 25 to apply a force urging the drill rod14 against the face being drilled, the force having a reaction R FIG. 8,b. means 36 to apply an opposite force V equal in magnitude and oppositein direction to the reaction producing a couple having a first momentM-1, c. means 34, 59, 55, 36 to apply an opposite restraining moment M-2equal in magnitude to the first moment, d. means 25, 72, 73 to effectcontrol of feed of the drill rod, constructed and arranged to effectthat feed of the drill rod is essentially motion of translation at adeterminate rate along the longitudinal axis produced, maintainingalignment as the drilling progresses.
 2. An apparatus as defined inclaim 1, and e. means 100 to move the drill in a direction opposite tothe feed.
 3. An apparatus as defined in claim 2 wherein the means a.applying the force includes i. a double acting fluid cylinder assembly25 having, a piston 26 with upper and lower faces, and aligned upper andlower piston rods 27A, 27B secured in the piston and being extensibleand retractible through upper and lower cylinder heads 28, 29 providinga range of motion of the cylinder relative to the piston, the pistonrods piston and cylinder having a common axis 30, upper and lowercylinder spaces 34, 35 being defined respectively between the upper andlower cylinder heads and the upper and lower faces of the piston, ii.means 80 to secure the drill to the cylinder, with the drill rodparallel to the common axis, iii. a support means 24 having an apex 24.1and means 60 to secure the upper piston rod at the apex, iv. means 62 todirect fluid under pressure to the lower cylinder space 35 with theupper cylinder space 34 then being connected to a bleeder pipe 72, thefluid under pressure acting upon the piston tending to move the cylinderdownward so applying the force to the drill rod, fluid in the uppercylinder space being free to discharge bleeding off through the bleederpipe.
 4. A combination as defined in claim 3 wherein, i. the means b toapply the opposite force includes means 36 anchoring a lower end of thelower piston rod in the face.
 5. A combination as defined in claim 4,the means anchoring the lower end of the piston rod including, ii. auniversal joint 38 the lower end of the lower piston rod being secured40 in the universal joint, a stub shaft 39 of the universal joint beingsecured in a hole 42 of the face.
 6. A combination as defined in claim3, the means d to effect control of feed including; i. a bleeder valve73 of the bleeder pipe, ratE of bleeding being controlled according toan amount by which the bleeder valve is opened, rate of relative motionof the cylinder to the piston and feed of the drill being a function ofthe amount by which the bleeder valve is opened.
 7. A combination asdefined in claim 6, wherein the means e to move the drill in a directionopposite to the feed includes i. means 62 to direct fluid under pressureto the upper cylinder space 34 the lower cylinder space 35 then beingconnected to the bleeder pipe, the lower cylinder space being free todischarge bleeding off through the bleeder pipe the fluid under pressureacting upon the piston applying a force urging the cylinder and thedrill to move upwards to pull the drill rod from a test hole drilled inthe face.
 8. A combination as defined in claim 7, the means 80 to securethe drill to the cylinder as aforesaid including, i. a guide rod 81having longitudinally spaced holes, ii. a bracket secured to thecylinder, the bracket having a sleeve 85 having an inside diameter suchas to accept the guide rod sliding therewithin, iii. a detent 87 of thebracket spring urged to enter a hole so as to lock the drill in aselected position with respect to the cylinder, constructed and arrangedfor the drill rod to be axially movable relative the cylinder throughouta range of travel between the selected positions.
 9. A combination asdefined in claim 8, and iv. a longitudinal groove extending between theholes, the detent engaging a sidewall of the groove when the drill ismoved axially as aforesaid, v. a latch pin 89 movable in a latch slot 90for latching the detent clear of the holes while still engaging thegroove sidewall.
 10. A combination as defined in claim 7, wherein themeans e. to move the drill rod in a direction opposite to the feedfurther includes, ii. a pulley 101 secured to the cylinder iii. a wedgeclamp means 114 having an eccentric cam 119 adapted to engage the drillrod, the wedge clamp being movable between upper and lower positions ofa range of motion relative to the drill rod, iv. a cable 108 passingaround the pulley and having one end secured to the clamping means withan opposite end secured in a fixed position so that force urging thedrill to move as aforesaid is applied by the cable to the wedge clampmeans.
 11. A combination as defined in claim 10 and wherein, iv. thewedge clamp has a lever, pivoted between inner and outer ends thereof,the cable being secured to the outer end of the lever, v. the eccentriccam being at the inner end of the lever and disengaged from the drillrod until force, applied as aforesaid by the cable to the outer end ofthe lever, rotates the lever engaging the eccentric cam with the drillrod so that, when the cylinder is moved alternatively upward anddownward, each time the cylinder is at a lowest position of its range ofmotion the eccentric takes a new grip on the drill rod so that it isprogressively pulled from the test hole.
 12. A combination as defined inclaim 3, wherein the means 60 to secure the upper piston rod at the apexof the support means includes, -a collar 53 having an inside diameter toaccept the upper piston rod sliding therethrough, -legs of the supportmeans being mounted in the collar to swing with respect thereto, -anupper adjustable stop 55 movable upwards and downwards on the piston rodand being securable to the piston rod bearing against an upper end wallof the collar.
 13. A combination as defined in claim 12 with ball andsocket means 47 mounting a leg in the collar.
 14. A combination asdefined in claim 12, the collar having a short hollow cylindrical sleeve137 FIG. 10 rotatable of the collar, a leg being mounted in the sleeveto swing with respect thereto.
 15. A combination as defined in claim 3,the double-acting fluid piston assembly further including vii. an uppercup seal 32 of flexible material, the seal having a base 32.1 and asidewall 32.2, the base being secured against an upper face of thepiston 26 so as to be concave upwards viii. a similar lower cup seal 32secured concave downwards to a lower face of the piston, adapted for thesidewalls of the seals to be expanded against the cylinder so as toeffect restraint against rotation of the cylinder with respect to thepiston.
 16. A combination as defined in claim 15, and means 62 to directfluid under pressure to one cylinder space 34 or 35 with fluid underpressure being in a remaining cylinder space 35 or 34, so as to expandthe cup seals as aforesaid.
 17. An apparatus as defined in claim 1, andmeans 100 to pull the drill rod from a test hole drilled in the face.